smith



J. A.. SMITH. BALANGBD PISTONI VALVE.

2 Sheets-Sheet 1.

(No Model.)

,550. Patented May 19, 1896.

HIHII (No Model.) 2 Sheets--Sheet` 2.

' J. A. SMITH. B-ALANGED PISTONVALVE.

No. 560,550. I Patented May 19, 1896.

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UNITED vSTATES PATENT OFFICE.

JOHN A. SMITH, OF JOHNSTOWN, PENNSYLVANIA, ASSIGNOR OF TVO-THIRDS TOJAMES HART AND ABRAHAM WILKINSON, OF SAME PLACE.

BALANCED PISTON-VALVE.

SPECIFICATION forming part ofV Letters Patent No, 560,550, dated May 19,189e.

Application led 511116 28, 1895.

T0 all whom, t may concern:

Be it known that I, JOHN A. SMITH, a citizen of the United States,residing at Johnstown, in the county of Cambria and State ofPennsylvania, have invented a new and useful Balanced Piston-Valve, ofwhich the following is a speciiication.

Myinvention relates to valves, an d particularly to balancedpiston-valves, the object in view being to provide a simple andeflicient form of valve in which the valve members are adapted to beclosed by the pressure of the fluid, the pressure being communicated tothe outlet-valve member in either position of the inlet-valve member.

Further objects and advantages of this invention will appear in thefollowing description, and the novel features thereof will beparticularly pointed out in the appended claims.

In the drawings, Figure 1 is a section of a valve constructed inaccordance with my i'nvention, both valve members being shown seated.Fig. 2 is a similar view showing the inlet-valve open or unseated. Fig.3 is a horizontal section on the plane indicated by the line 3 3 ofFig. 1. Fig. 4 is a detail View of the cap forming one of theequalizing-chambers detached.

Similar numerals of reference indicate corresponding parts in all theigures of the drawings.

Formed in the valve-casing 1 are the parallel bores or cylinders 2 and3, with which communicate, respectively, the inlet and outlet ports 4cand 5. The cylinder-port 6 is arranged in the wall or partition betweensaid bores or cylinders and communicates with the latter by means ofports 7 and 8, respectively. v

Arranged in each bore or cylinder is avalveseat 9, the seat in the inletbore or cylinder 2 being arranged between the planes of the inlet-port 4and communicating-port 7, and the seat in the outlet bore or cylinderbeing located between` the communicating-port 8 and the outlet-port 5.In the construction illustrated said valve-seats are threaded in thebores or cylinders; but it is obvious that they may be secured in placein any other suitable manner to provide for their removal Serial No.554,359. (No model.)

when it is necessary that they should be replaced or repaired.

The inlet and outlet valve members 11 and 12 are carried by the stems 13and 14, which are arranged axially in the bores orcylinders,compressible packing 15 being secured in contact with the face of eachvalve member by means of a compressing disk or nut 1G. The bores orcylinders are preferably enlarged, as shown at 17, contiguous to eachvalve-seat to provide space for the operation of the valve member, andthe portions of the valve members remote from their faces are reduced,as shown at 18, to operate in the reduced portions 19 of the bores orcylinders, said reduced portions being l'itted with caps 20,Which formequalizing-chambers 21. These reduced portions 18 of the valve membersfit in the equalizing-chambers and are provided with packing-rings 22 ofcompressible material, heldin place by means of disks 23 and nuts 24:.

The equaliZing-chambers are in communication with each other through theconnecting-channel 25, which is formed in the partition or wallinterposed between the bores or cylinders, the cylindrical inclosedportions of the caps 20 having openings 2,6, which communicate with saidchannel at its extremities.

The stem of the inlet-valve member 11 is provided with an axial bore' orchannel 27, extending from a point below the valve member to the upperextremity, and therefore communicating at its opposite ends with themain portion of the bore or cylinder and the equalizing-chamber, andtherefore the pressure of the fluid contained in the main portion of thebore or cylinder is communicated through the axial channel of the stemto the equalizing chamber above the inlet -valve member to balance thepressure upon opposite sides of the valve member, and this pressure inthe equalizing-chamber of the inletvalve member is communicated throughthe connecting channel 25 to the equalizingchamber of the outlet-valvemember, whereby pressure is exerted upon the rear side or the pistonextension of the outlet-valve. Hence when there is pressure in the bodyportion of the outlet-valve-member bore or cylinder, caused by pressurein the cylinder IOO with which the port 6 communicates, the pressureupon opposite sides of both inlet and outlet valve members is equalized.

Secured to the stems of the valve members and operating in the bores orcylinders upon the opposite sides of' the valve member from saidequalizing-chambers are plungers 28,also provided with packing-rin gs29, and therefore, inasmuch as these plungers are exposed at all timesto the pressure in the body portions of the bores or cylinders, thepressure of the fluid will tend to close or seat the valve members ifthey are unseated or hold them seated :if they are in their normalpositions. In other words, the plun gers, by reason of the constantpressure thereon, operate to close and hold the valve members seated,whereby when it is necessary to unseat a valve to supply fiuid to thecylinder or exhaust therefrom it is necessary to produce the necessarymotion of the valve member by mechanical means, such as anoperating-lever 30, which I have shown fulcrumed at 3l and provided withbearingpoints 32 and 33 to engage the exposed extremities of thevalve-stems. It is unnecessary to connect the operating-lever with thevalve-stems, for the reason that as soon as the valve members arereleased by the removal of positive pressure against their stems saidvalve members will be closed by the pressure of the Huid. By theconstruction above described both valves cannot be open simultaneously,for the reason that pressure must be removed from one valve-stem beforeit can be applied to the other, and as soon as the pressure is removedthe valve member is seated by Huid-pressure.

It will be understood that the improved valve may be applied to use inconnection with steam, hydraulic, pneumatic, and other cylinders, ormechanisms employing` fluidpressure of different classes, and thatvarious changes in the form, proportion, and the minor details ofconstruction may be resorted to without departing from the spirit orsacrificing any of the advantages of this invention.

Having described my invention, what I claim is* 1. A valve having acasing provided with inlet and outlet cylinders respectively havinginlet and outlet ports and communicating with a cylinder-port,valve-seats arranged between the planes of the ports communicating withthe cylinders, equalizing-ehambers permanently exposed tocylinder-pressure, and valve members arranged in the cylinders andhaving their rear sides exposed in the equalizing chambers, whereby thevalves when released are seated by the said pressure in theequalizing-ehambers, substantially as specified.

2. A valve having inlet and outlet cylinders provided, respectively,with inlet an d outlet ports and communicating With a cylinder-port,seats arranged in the cylinders bctween the planes of the portscommunicating therewith,valve members arranged in the cylinders andhaving piston extensions operating in equalizing-chambers which arerespectively in communication with the cylinders and exposed tocylinder-pressiue, the stem of the valve member operating in theinletcylinder being bored to form a channel connecting the body portionof the cylinder with the communicating eqnalizing-chamber, and plungerscarried respectively by the stems of the valve members and exposed to aconstantpressure of fluid in the body portions of thc cylinders,substantially as specified.

3. A valve having inlet and outlet cylinders provided respectively withinlet and outlet ports and communicating with a cylinderport, capsremovably fitted in the extremities of the cylinders to formequalizing-ehambers exposed to cylinder-pressure, valve members arrangedrespectively in the cylinders and having piston extensions fitted in theequalizingchambers, means for communicating pressure from the inlet-portto the equalizing-ehamber at the end of the inlet-cylinder, and plungersconnected to the stems of the valve members and exposed to a constantpressure of fluid in the cylinders, substantially as specified.

In testimony that I claim the foregoing as my own I have hereto affixedmy signature in the presence of two witnesses.

JOI-1N A. SMITH. lVitnesses M. B. STEPHENS, FRANK E. REEsn.

